EP 0723371 B1 20020417 - Method and apparatus for protecting control signals in a conditional access system
Title (en)
Method and apparatus for protecting control signals in a conditional access system
Title (de)
Vorrichtung und Verfahren zum Schutz von Steuerbefehlen in einem System mit bedingtem Zugriff
Title (fr)
Procédé de protection des messages de gestion d'un système de controle d'accès et dispositif pour sa mise en oeuvre
Publication
Application
Priority
FR 9500464 A 19950117
Abstract (en)
[origin: EP0723371A1] The method involves sending service attribute messages (SA) at 1-second intervals to a circuit (1) which inserts a check word (CW). Another circuit (2) introduces the number (3) of negative management messages (EMMN) sent since the last access control message (ECM). The current check word is stored (4) for insertion (5) into the EMMN to authenticate it w.r.t. the current service sequence. The next stage (6) increments the stored number of EMMNs and a circuit (7) calculates the compression of bytes in the message (EMM1) and one of four secret keys by a known hashing function. The other secret keys are applied to encryption circuits (8,9) and a compression calculation device (10) for the positive management message (EMMP).
IPC 1-7
IPC 8 full level
H04H 1/00 (2006.01); H04H 20/00 (2008.01); H04K 1/00 (2006.01); H04N 7/16 (2006.01); H04N 7/167 (2006.01)
CPC (source: EP)
H04N 7/163 (2013.01); H04N 7/1675 (2013.01)
Designated contracting state (EPC)
DE FR GB IT
DOCDB simple family (publication)
EP 0723371 A1 19960724; EP 0723371 B1 20020417; DE 69620660 D1 20020523; DE 69620660 T2 20021031; FR 2729521 A1 19960719; FR 2729521 B1 19970307; JP 3863587 B2 20061227; JP H08307850 A 19961122
DOCDB simple family (application)
EP 96400070 A 19960111; DE 69620660 T 19960111; FR 9500464 A 19950117; JP 572296 A 19960117